Double acting actuators have been used for years to provide two opposing directions of powered actuation from a single actuator. Double actuating actuators can be actuated by a fluid that is compressible or incompressible such as air or hydraulic fluid respectively. There are many uses for dual acting cylinders in the material handling world. For example, dual acting cylinders might be used to actuate diverts to divert moving articles from one conveying surface to another, block articles on a conveying surface, or might be used to move articles from one location to another during the loading, unloading, and storage of articles.
The world of material handling can involve the acquisition and movement of articles that range from small and light to large and heavy. As a consequence, material handling equipment must be rugged, durable, and fragile areas must protect from unintended bumps and collisions. In some cases, the material handling equipment must be small enough to fit into tight spaces. Some dual acting cylinders can have a hollow rod that extends out the front and the back ends of the cylinder and reciprocates longitudinally relative to the cylinder. This arrangement prevents communication of the hollow of the hollow shaft with the insides of the cylinder, but adds additional length to the dual acting cylinder. Flexible tubing can be attached to the back end of the hollow rod to communicate air or vacuum to the front end of the hollow rod as it reciprocates, but this adds even more length to the dual acting cylinder and exposes two ends of the hollow rod and the flexible tubing to potential damage. What is needed is a dual acting cylinder that is short in length, and protected from unintended bumps and collisions.